I have a Sig SE and I went and ordered an Irvine .53 motor. It's the same size as the .46 OS, and even uses the same mounting holes. If you change out the muffler (with a .46 OS I might add) it's the exact same weight and size. You can pick up one of these for around $100 -120 dollars from www.justengines.org. These huge motors that people are putting on their engines are just way too big (and ugly). The plane is designed for a .45 or so engine. the .53 is absolutely perfect because it's the same size. With a good 11.6 or 11.7 prop, the thing is a screamer. No need to change out the landing gear on this